New System Quells Threat Of Wind Shear To Aircraft

December 9, 1999|By KEN KAYE Staff Writer

The 38,000 passengers who use Fort Lauderdale-Hollywood International Airport each day are now protected against deadly wind shear.

Their guardian angel: a $4.7 million Terminal Doppler Weather Radar, which allows air traffic controllers to detect everything from a gentle wind shift to a powerful downdraft within a 50-mile radius of the airport.

That information is immediately passed along to pilots, allowing them to take action to avoid dangerous wind conditions.

"It's absolutely accurate," said Harley Mumma, an air traffic control supervisor in the Fort Lauderdale airport tower. "When there is a wind shear, we'll hear a horn. It's a piece of cake to use."

Although Fort Lauderdale's Doppler system had been in use for several months under a testing phase, the Federal Aviation Administration on Wednesday said it is officially on-line.

In addition to the safety cushion, passengers also should be given a smoother ride courtesy of Doppler, said Jim Reynolds, airport spokesman.

"The controllers should be able to divert planes around the clouds," he said. "It's a major safety enhancement."

Wind shear, or two conflicting currents of air, can result in an airplane rapidly losing airspeed or lift. That can be particularly perilous when a plane is low and slow on final approach or just after takeoff.

Wind shear has been blamed for at least three major U.S. airliner crashes since 1985 and may have been a factor in the crash of an American Airlines jetliner in Little Rock, Ark., that killed 11 in June.

To trace shear, the Doppler radar relies on a 14-story tower capped with a soccer-ball-like dome 33 feet in diameter. The radar emits an electromagnetic beam that swivels back and forth, much like a sprinkler head.

The tower sits 12 miles northwest of the Fort Lauderdale airport near the intersection of the Sawgrass Expressway and Sunrise Boulevard.

Information from the tower is fed into a computer terminal in the 16-story control tower at Fort Lauderdale-Hollywood International. Its screen shows a simple graphic of the airport and its approach paths.

If there is so much as a 7 mph wind conflict, a small purple line will show its exact location. If dangerously strong winds arise, the screen will flash a small red box that says, "Microburst."

In any case, there will be a beeping horn.

A microburst is a powerful downdraft associated with wind shear. The most dangerous wind shear is created by thunderstorms.

"With Doppler, we can see it coming and make a plan," said Don Starbuck, the Fort Lauderdale tower's operational supervisor.

Before Doppler, controllers used a low-level wind shear alert system, which had sensors on the four corners of the airport.

"The problem was, we didn't know about the shear until it was already here," Starbuck said.

It was a ferocious microburst that slammed a Delta Air Lines jumbo jet to the ground short of a runway at Dallas-Fort Worth International Airport on Aug. 2, 1985, killing 136 of the 163 on board as well as a motorist on the ground.

After that disaster, the FAA decided to install the Doppler radar at 45 commercial airports, based on the number of thunderstorms, the volume of air traffic and the number of passengers an airport sees.

South Florida sees thunderstorms between 80 and 100 days a year, more than any other part of the country. The radar was already operating at Miami and Palm Beach international airports.